1. Field of the Invention
The present invention relates to an image forming apparatus.
2. Description of the Related Art
Japanese Patent Laid-Open No. 9-237027 discloses an image forming apparatus in which an image forming chamber in which a photosensitive drum and an exposure device are disposed is separated from a heat-fixing chamber by a partition plate. In this image forming apparatus, a fan provided in the partition plate rotates in normal and reverse directions. For example, when the temperature in the image forming chamber is lower than a desired temperature, air heated in the heat-fixing chamber is supplied to the image forming chamber. When the temperature in the image forming chamber is higher than a desired temperature, air heated in the image forming chamber is supplied to the heat-fixing chamber. As a result, the temperature of air inside the image forming chamber is maintained to a desired temperature.
However, even when the image forming chamber and the heat-fixing chamber are divided by the partition plate, it is necessary to convey a recording material from the image forming chamber to the heat-fixing chamber in order to heat-fix a recording material in which an image is not fixed. Thus, an opening through which the recording material is delivered needs to be formed in the partition plate.
Sine the opening is present, hot air moved from the image forming chamber to the heat-fixing chamber may be further heated in the heat-fixing chamber and may return to the image forming chamber through the opening of the partition plate. As a result, the temperature in the image forming chamber may increase so that electrical characteristics of respective components may change and a large displacement between components may occur with a change in the temperature of the environment where the image forming apparatus is used.
Moreover, the hot air in the heat-fixing chamber may enter the image forming chamber when the opening of the image forming chamber is very close to the opening of the heat-fixing chamber or depending on a pressure relation near the openings.